Horizontal Diversification and Vertical Contracting: Firm Scope and Asset Ownership in Taxi Fleets

This paper considers the vertical implications of horizontal diversification. Many studies have documented organizational problems following corporate diversification. We propose that selective vertical dis-integration � shifting asset ownership to agents � can mitigate rent-seeking and coordination failures in the diversified firm. We test this proposition in a particularly simple setting that allows us to isolate the effects of interest and control for the likely endogeneity of diversification: taxi fleets that diversify into the limousine, or black car, segment following a wave of entry deregulation in the early 1990s. The results show that taxi fleets are substantially more likely to use owner-operator drivers following diversification. Moreover, diversified fleets that use a greater share of owner operators are more productive than diversified fleets that own most of their vehicles. We interpret these findings as evidence that firms re-organize in response to the challenges of diversification, and that there are causal links between the horizontal and vertical boundaries of the fleet.